Many control and access environment structures require that storage for a procedure activation exist at times when control is not nested within the procedure activated. This is straightforward to implement by dynamic storage allocation with linked blocks for each activation, but rather expensive in both time and space. The paper presents an implementation technique using a single stack to hold procedure activation storage which allows retention of that storage for durations not necessarily tied to control flow. The technique has the property that in the simple case, it runs identically to the usual automatic stack allocation and deallocation procedure. Applications of this technique to multi-tasking, coroutines, backtracking, label-valued variables, and functional arguments are discussed.